This invention relates to motor driven tools having a rotatively driven tool-holding collet and, more particularly, to an arrangement for locking the collet from rotation.
In recent years, battery powered motor driven screwdrivers have become increasingly popular. However, due to the limitations of motor size and available battery power, there arise situations where the power tool cannot generate sufficient torque to properly seat a driven screw. Accordingly, it is a primary object of this invention to provide an arrangement whereby the tool operator can lock the tool holding collet to the housing so that sufficient torque can be manually applied to the screw or other driven device.
Typical battery powered screwdrivers include a high speed motor whose output shaft is coupled to a gear train for providing output rotation at a greatly reduced speed. In such an arrangement, if the output shaft is prevented from turning and power is applied to the motor, there exists the danger that either the motor or the gear train will be damaged. Further, if a collet locking arrangement is designed to either lock up the gear train or lock the collet to the housing without separating it from the gear train, if motor power is accidentally applied to the motor when the collet is locked, the same likelihood of damage occurs. Also, if the locking arrangement locks up the gear train, when manual torque is applied to the tool, the gear train is likely to be damaged. Accordingly, it is a further object of this invention to provide a collet locking arrangement which both locks the collet to the housing and disengages it from the drive train.